This invention relates in general to photonic crystals, and in particular to photonic crystal reflectors or filters and their applications, such as in displacement sensing.
Micro-Electrical-Mechanical-Systems (MEMS) technology provides important mechanisms for tuning and switching a wide variety of optical devices such as sensors, filters, modulators, switches, and lasers. See, for example, the following references:    1. “Sub-10 cm3 interferometric accelerometer with nano-g resolution” by N. C. Loh, M. A. Schmidt, S. R. Manalis, J. Microelectromechanical Syst. 11, 181 (2002);    2. “The Polychromator: A programmable MEMS diffraction grating for synthetic spectra”, Technical Digest. Solid-State Sensor and Actuator Workshop, pp. 89-92, Hilton Head Island, SC, USA, 4-8 Jun. 2000, by G. B. Hocker, D. Youngner, E. Deutsch, A. Vol Volpicelli, S. Senturia, M. Butler, M. Sinclair, T. Plowman, A. J. Ricco;    3. “Deformable grating optical modulator”, by O. Solgaard, F. S. A. Sandejas, D. M. Bloom, Opt. Lett. 17, 688 (1992);    4. “Scalable optical cross-connect using micromachined mirrors”, by P. M. Hagelin, U. Krishnamoorthy, J. P. Heritage, O. Solgaard, IEEE Photonics Technol. Lett. 12, 882 (2000); and    5. “Tunable VCSEL”, by C. J. Chang-Hasnain, IEEE J. Sel. Topics Quantum Electron. 6, 978 (2000).
The success of these microoptomechanical devices relies on the fact that the mechanical motion required for their operation is relatively small; on the order of the operating wavelength for high-contrast devices, and only a small fraction of a wavelength for some sensors and lasers. Reducing the required displacement is of great interest in optical MEMS research, because it decreases the required actuation force and enables smaller devices with higher response speed. It is therefore desirable to provide an improved system whereby the required actuation force and smaller devices with higher response speeds can be achieved. It is further desirable to provide optical devices with improved optical characteristics that can be used for such systems and for other purposes.